[rtcweb] STUN for keep-alive

Christer Holmberg <christer.holmberg@ericsson.com> Wed, 14 September 2011 09:46 UTC

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From: Christer Holmberg <christer.holmberg@ericsson.com>
To: "rtcweb@ietf.org" <rtcweb@ietf.org>
Date: Wed, 14 Sep 2011 11:48:43 +0200
Thread-Topic: STUN for keep-alive
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Subject: [rtcweb] STUN for keep-alive
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Assuming we would use ICE for media authorization, it has been indicated that, for legacy interoperability, a gateway would be required in many cases (as the legacy entities might not support ICE).

ICE "bundles" functions together, meaning that if you use STUN for media authorization purpose (which is a part of the connectivity check purpose), you will also use STUN for keep-alive purpose (for UDP based media).

My question is: would we be able to relax the requirement to use STUN for keep-alive? Because, eventhough the keep-alives messages aren't authenticated, and do not trigger responses, a gateway would still have to process them, and since a gateway typically would serve a large number of browser clients, that could have quite big performance impact (the number of STUN keep-alives sent per session of course depend on how much other media traffic there is, but still).

So, for RTP based media, one could use RTP, and for UDP based data channels "dummy" UDP packets (unless there is a protocol on top of UDP which provides a keep-alive mechanism itself).